Electrical percolation and dynamic piezoresistivity of silver nanoparticle/polydimethylsiloxane films

Abstract

Electrical percolation and piezo-resistivity under cyclic load were studied for silver nanoparticle (AgNP)/polydimethylsiloxane (PDMS) films. Attention was focused on the percolation process and the impacts of the percolation stage and load frequency on the piezoresistivity of the films. A power law was uncovered between the electrical resistance and the surface mass density ( m _d ) of AgNP layer. Dependence of piezoresistive sensitivity and linearity on m _d and cyclic load frequency were also investigated and interpreted in terms of the physical changes of the AgNP layer and the dynamics of the strain-induced microcracks. In particular, a peak gauge factor 75 was achieved at m _d = 0.32 mg cm ^− ^2 and the load frequency 0.5 Hz , and excellent linearity was found at the frequency 1 Hz or higher. These new findings provide important guidance for the design and applications of AgNP/PDMS films in body motion tracking, fatigue load monitoring and surface vibration detecting.

Keywords

• nanoparticles
• piezo-resistivity
• electrical percolation
• polymer
• stress sensor